1. Field of the Invention
The present invention generally relates to a fire protection system for vertical surfaces and in particular to a fire protection system for walls, wherein the system is stable in an environment of extreme heat and flames to provide long lasting fire protection to vertical surfaces.
2. Description of the Background Art
There are three major types of materials that have been used to protect walls and flat surfaces from excessive heat and flame to retard both the damage caused by the fire and the spreading of the fire. These three types of material are: (1) insulative materials, (2) endothermic materials, and (3) intumescent coatings and materials.
The use of insulative materials such as alumina silica blankets and boards, or mineral wool blankets and boards are problematic because the materials are typically very thick and/or heavy. These materials are bulky and difficult to install. In addition, insulative materials can become detached from vertical surfaces when the heat of a fire expands or destroys the means by which the insulative materials are attached to the walls.
Endothermic materials are composed of compounds that activate in a fire situation by breaking down at the molecular level and releasing trapped water which then cools the protected item. The most common example of this is alumina tri-hydrate, which is a dry white powder that releases large amounts of water at about 1,100xc2x0 F. A well-known endothermic product is the INTERAM(trademark) E-50series flexible wrap systems available from 3M Fire Protection Products, St. Paul, Minn. The thickness problem inherent in insulation systems is somewhat lessened, but endothermics have their own problems. Due to the fact that the material has water molecules trapped in dry form, the system tends to be quite heavy. Furthermore, there is no successful method suggested for installing such materials on a vertical surface. When the 3M INTERAM(trademark) E-50 system is installed on electrical conduits or cable trays, it is installed in several layers with careful sealing at all seams to hold in the water that will be released in a fire. Thus, the INTERAM(trademark) E-50 system is difficult to install and had high associated labor costs. Also, once installed, these systems are extremely difficult to remove and replace in order to do maintenance work or to update electrical and communication networks buried within a wall.
Intumescent materials are products that xe2x80x9cgrowxe2x80x9d or xe2x80x9cthickenxe2x80x9d only when exposed to heat, creating an insulation layer that separates the protected item from the fire. One major advantage of intumescent materials is that the unreacted material is thin and lightweight. Intumescent materials are also easier to install. In fact, intumescent materials are often applied as a lightweight coating over the area to be protected. Yet there are two severe problems with spray-on intumescent coatings.
(1) The carbonaceous xe2x80x9cfoamxe2x80x9d that results when the intumescent materials expand upon exposure to heat is always fragile and is generally damaged by the turbulence of a fire. In addition, expanded intumescent materials will fall off of the coated surfaces due to the pull of gravity. This fragile nature of intumescent materials leads to the formation of xe2x80x9cfissuresxe2x80x9d in the material which allow heat to penetrate to the protected surfaces. These fissures appear randomly and give the system a quality of unpredictability that is undesirable for fire protection systems.
(2) Furthermore, when expanded intumescent materials are exposed to direct fire and heat, the outer carbonaceous foam that is in direct contact with the fire tends to erode, thus exposing lower layers of the materials. The lower layers also erode, causing a geometric reduction of the effectiveness of the product over time. This eroding effect accelerates the growth of the above mentioned fissures and magnifies the unpredictability of the system.
U.S. Pat. No. 5,681,640 describes a multi-layered, flexible material containing a plurality of layers of intumescent materials that provides one solution to containment of the carbonaceous foam. The multi-layered materials contain folds that expand with the expansion of the intumescent materials and stabilize the carbonaceous foam resulting from the expansion of the intumescent materials. However, the described fire protection system is designed to protect conduit, cable trays, support rods, and structural steel. The material is made to wrap around a protected area with the ends of the wrap being fastened together. There is no hint of how one might apply the described material to a wall in a way that would protect the wall anchor from the extreme heat of a fire.
Gravity works to pull down any fire protective system applied to large vertical surfaces such as walls. Under normal conditions, attaching the fire protective system to a wall with adhesives, nails or screws can defeat gravity. However, as a fire begins and temperatures rise above 500xc2x0 or 1000xc2x0 F. adhesives melt and metal components such as nails and screws expand. As fastening components expand, they become longer and loosen their grip on the fire protection system thereby allowing it to be pulled off the wall by the weight of the system.
Accordingly, a need exists for a fire protective system that can take advantage of the favorable qualities of intumescent materials to protect large vertical surfaces, such as walls. A further need exists for stabilizing the expanded carbonaceous foam of activated intumescents applied to large vertical surfaces against the pull of gravity. A fire protective system is needed that can be installed on walls that will remain in place during the extreme heat generated during a fire.
The present invention includes a passive fire protection system for the protection of vertical walls against flames and heat in a severe total environment type fire. The system includes a multi-layered, flexible material containing at least one layer of intumescent material. This multi-layered material is configured such that it provides a containment system for the carbonaceous foam resulting from the expansion of the intumescent. The protective sheets include a set of protective sheets having a J-fold on a first side, the J-fold formed by the inward folding of a side of the sheets; a set of protective sheets having a Z-fold at a bottom end, the Z-fold having a first fold upward and a second fold downward; and a set of sheets having a top-fold at a top end, the top-fold formed by the downward folding of a top side of the sheets. The fire protective system also includes mounting bars and wall anchors for attaching the protective sheets to the wall, strips of fire protective material for underlaying seams of adjoining protective sheets, fasteners for securing adjoining pieces of protective sheets to form a seam; and fire resistant adhesive tape.
In accordance with another aspect of the invention, a fire protection system for walls comprises: (a) multi-layered flexible protective sheets containing at least one layer of an intumescent; (b) mounting bars and wall anchors for attaching the protective sheets to a wall, the mounting bars and wall anchors being protected from intense heat by the protective sheets; (c) fasteners for securing adjoining pieces of protective sheets to form a seam; and (d) fire resistant adhesive tape used to hold seams and folded protective sheets into place.
Yet another aspect of the invention is an installation process whereby the attachment of the multi-layered protective sheets to vertical surfaces is protected from the extreme heat of a fire. The installation process includes:
(a) installing the protective sheets having a Z-fold along a bottom section of the wall adjoining a floor, the first fold being attached to the wall with a first mounting bar and a first wall anchor, and the second fold secured to the wall with a nail or screw, wherein the second fold covers the first mounting bar and the first wall anchor used to attach the first fold to the wall;
(b) installing protective sheets vertically up the wall by mounting a pair of protective sheets to the wall with a second mounting bar and a second wall anchor, flipping the top protective sheet over the second mounting bar and the second wall anchor to cover the second mounting bar and the second wall anchor;
(c) installing the protective sheets having a top-fold to a top section of the wall adjoining the ceiling by securing the top end of the top-folded protective sheets to the top section of the wall, wherein the top-fold is folded over a third mounting bar and a third wall anchor and secured to the surface of the protective sheet with a fire resistant adhesive tape;
(d) connecting adjacent protective sheets having a J-fold, wherein a strip of a fire protective material is secured to the wall under an overlapping area comprising the J-fold of one protective sheet and a section of one side of another protective sheet, the overlapping area being secured together with a plurality of fasteners to form a seam, wherein the seam is folded flat and taped down with a fire resistant adhesive tape; and
(e) repeating steps (a) through (d) as needed to cover the surface of the wall.
The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and the specific embodiments disclosed might be readily utilized as a basis for modifying or designing other structures for carrying out the same purpose of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.